Overcharge protection systems for prismatic lithium ion battery cells with biased packaging

Abstract

A prismatic lithium ion battery cell includes a packaging having a cover. A power assembly disposed within the packaging has a first (e.g., negative) side and a second (e.g., positive) side. A terminal pad is electrically coupled to the first side, while the cover is electrically coupled to the second side, of the power assembly. The cover includes a spiral disk feature disposed below the terminal pad and a reversal disk disposed below the spiral disk feature. The reversal disk is configured to deflect upwards to displace the spiral disk feature to contact the terminal pad in response to a pressure within the packaging being greater than a first predefined pressure threshold, forming an external short-circuit between the first and second sides of the power assembly. Subsequently, a portion of the power assembly fails in response to the external short-circuit and interrupts current flow within the power assembly.

The invention claimed is: 
     
       1. A battery cell, comprising:
 a packaging including a cover and a can, the cover being sealed to the can; 
 a power assembly disposed within the packaging, the power assembly being configured to have a current flow and having a first side and a second side; 
 a terminal pad electrically coupled to the first side of the power assembly, the cover being electrically coupled to the second side of the power assembly; and 
 the cover including:
 a spiral disk disposed below the terminal pad and a reversal disk disposed below the spiral disk, the spiral disk including a central portion and a plurality of legs, the central portion being directly coupled to the cover via the plurality of legs, the reversal disk being configured to deflect upwards to push at least the central portion of the spiral disk and to cause at least the central portion to contact the terminal pad in response to a pressure within the packaging being greater than a first predefined pressure threshold, the central portion remaining directly coupled to the cover via the plurality of legs and forming an external short-circuit between the first and second sides of the power assembly when the central portion is in contact with the terminal pad, a portion of the power assembly failing in response to the external short-circuit and interrupting the current flow of the power assembly. 
 
 
     
     
       2. The battery cell of  claim 1 , wherein the first side of the power assembly is a negative side of the power assembly and the second side of the power assembly is a positive side of the power assembly. 
     
     
       3. The battery cell of  claim 1 , wherein the spiral disk is integrated into the cover and formed in relief. 
     
     
       4. The battery cell of  claim 1 , wherein the cover comprises a vent disk configured to activate to release an effluent from an interior of the packaging at a second predefined pressure threshold, and wherein the first pressure threshold is substantially less than the second pressure threshold. 
     
     
       5. The battery cell of  claim 4 , wherein the second predefined pressure threshold is at least 50% greater than the first predefined pressure threshold. 
     
     
       6. The battery cell of  claim 1 , wherein a portion of the external short-circuit traverses at least the terminal pad, the spiral disk, and the cover of the packaging of the battery cell. 
     
     
       7. The battery cell of  claim 1 , comprising a terminal insulator disposed between the cover and the terminal pad that electrically isolates the cover from the terminal pad, wherein the terminal insulator defines an opening that allows at least the central portion of the spiral disk to be displaced through the opening to contact the terminal pad. 
     
     
       8. The battery cell of  claim 1 , wherein the power assembly comprises:
 a coil stack with at least one coil; 
 a first current collector coupled to a first electrode of the at least one coil to form the first side of the power assembly; 
 a second current collector coupled to a second electrode of the at least one coil to form the second side of the power assembly; 
 a first terminal post that extends through the cover and is coupled to the first current collector and the terminal pad; and 
 a second terminal post that is coupled to the second current collector and to the cover. 
 
     
     
       9. The battery cell of  claim 8 , wherein the at least one coil comprises a coil stack having two or more coils. 
     
     
       10. The battery cell of  claim 8 , wherein the first or second current collector is the portion of the power assembly that fails in response to the external short-circuit to interrupt the current flow, the current flow being at least between the first side and the second side of the power assembly. 
     
     
       11. The battery cell of  claim 8 , wherein at least one of the first and the second current collector that fails includes a fuse that is designed to melt and fail before other portions of the power assembly to interrupt the current flow, the current flow being at least between the first and second sides of the power assembly in response to the external short-circuit. 
     
     
       12. The battery cell of  claim 1 , wherein, before the external short-circuit is formed in response to the pressure within the packaging, the terminal pad is electrically isolated from the cover. 
     
     
       13. The battery cell of  claim 1 , wherein the battery cell has a capacity of at least 100 amp hours (Ah). 
     
     
       14. The battery cell of  claim 1 , wherein the battery cell is part of a lithium ion battery module. 
     
     
       15. The battery cell of  claim 14 , wherein the lithium ion battery module is part of a stationary energy storage system. 
     
     
       16. A battery cell, comprising:
 a packaging including a cover and a can, the cover being sealed to the can; 
 a power assembly disposed within the packaging, the power assembly being configured to have a current flow, the power assembly comprising:
 a coil stack with at least one coil, the at least one coil having a positive electrode and a negative electrode; 
 a first current collector coupled to the negative electrode of the at least one coil; 
 a second current collector coupled to the positive electrode of the at least one coil; 
 a first terminal post coupled to the first current collector, the first terminal post extending through the cover; 
 a second terminal post coupled to the second current collector and to the cover; and 
 
 a first terminal pad coupled to the first terminal post; 
 a second terminal pad coupled to the second terminal post; and 
 the cover including a spiral disk disposed below the first terminal pad and a reversal disk disposed below the spiral disk, the spiral disk including a central portion and a plurality of legs, the central portion being directly coupled to the cover via the plurality of legs, the reversal disk being configured to deflect upwards and to push at least the central portion of the spiral disk to contact the first terminal pad in response to a pressure within the packaging being greater than a first predefined pressure threshold, the central portion remaining directly coupled to the cover via the plurality of legs and forming an external short-circuit between the positive and negative electrodes of the power assembly when the central portion is in contact with the first terminal pad, a portion of the power assembly failing in response to the external short-circuit and interrupting the current flow of the power assembly. 
 
     
     
       17. The battery cell of  claim 16 , wherein the first spiral disk is integrated into the cover and formed in relief. 
     
     
       18. The battery cell of  claim 16 , wherein the cover comprises a vent disk configured to activate to release an effluent from an interior of the packaging at a second predefined pressure threshold, wherein the second predefined pressure threshold is at least 50% greater than the first predefined pressure threshold. 
     
     
       19. The battery cell of  claim 16 , wherein a random portion of at least one of the first and second current collector is the portion of the power assembly that fails in response to the external short-circuit to interrupt the current flow, the current flow being at least between the first and second terminal pads. 
     
     
       20. A battery cell, comprising:
 a packaging including a cover and a can, the cover being sealed to the can; 
 a power assembly disposed within the packaging, the power assembly being configured to have a current flow and comprising:
 a positive side and a negative side, the packaging being electrically coupled to the positive side of the power assembly; 
 
 a terminal pad disposed above the cover of the packaging and electrically coupled to the negative side of the power assembly; and 
 the cover including:
 a spiral disk disposed below the terminal pad and a reversal disk sealed to the cover below the spiral disk, the spiral disk including a central portion and a plurality of legs, the central portion being directly coupled to the cover via the plurality of legs, the reversal disk being configured to deflect upwards to push at least the central portion of the spiral disk and to cause at least the central portion to contact the terminal pad in response to a pressure within the packaging being greater than a first predefined pressure threshold, the central portion remaining directly coupled to the cover via the plurality of legs and forming an external short-circuit between the positive and negative sides of the power assembly when the central portion is in contact with the terminal pad; and 
 a vent disk sealed to the cover and configured to activate to release an effluent from an interior of the packaging at a second predefined pressure threshold, the first predefined pressure threshold being less than the second predefined pressure threshold. 
 
 
     
     
       21. The battery cell of  claim 20 , wherein the second predefined pressure threshold is at least 50% greater than the first predefined pressure threshold.